This invention relates to body support arrangements, particularly for beds.
Ordinarily, beds have a body support arrangement formed by a base overlaid by a mattress, and there has evolved a considerable variety of spring or filled mattresses, the spring arrangements or the fillings such as foam rubber being such as to offer a wide variety of firm to soft mattresses to suit a potential user.
Whilst mattresses can be laid on a firm, unyielding base, it has long been recognised that a greater degree of comfort can be provided to the user if the base itself is sprung, by a spring arrangement that has its own characteristics to add to or complement the spring or filled mattress.
Conventional beds for normal use are formed by a sprung base with a horizontal surface on which the mattress is laid. However, when it comes to beds for users with a need or a preference to use a bed other than flat, sections of the bed are frequently required to be raised or lowered, such as, for example, to raise the upper body to an approximate sitting position, or to raise or bend the legs.
Conventional beds are not conducive to this. The presence of a spring base impedes the correct location of lifting and lowering mechanism for the mattress, and if such mechanism is applied solely to the mattress, an attempt to lift a section of it would simply result in the mattress bending or folding and cause rucking on its surface such as to render it unuseable.
To combat this, the common practise is to dispense with a sprung base and to lie the mattress on a rigid platform, sections of which can be lifted and lowered to cause sections of mattress to assume a required disposition to suit the needs or the requirements of a user, but at the expense of detracting from the total comfort and support available in conventional beds.
A further factor when conventional mattresses are laid on a rigid platform with adjustable sections, is that when one section is pivotally attached to an adjacent section and adjusted from an in-line condition to a condition where the included angle between the said sections is less than 180xc2x0, a fold, more a number of folds are caused in the upper surface of the mattress, to the noticeable discomfort of the user, and an increased risk of the creation of bed sores when the person using the bed must, due to a medical condition, lie on it for considerable periods.
The object of the invention is to provide a body support arrangement that avoids the disadvantages mentioned above.
According to the present invention, a body support arrangement comprises an array of springs extending between the upper and lower outer surfaces of a generally rectangular piece of a resilient and compressible material, the springs lying in passageways through the thickness of the resilient material, which passageways have one dimension substantially equal to the diameter of the springs, and a dimension perpendicular thereto greater than that of the diameter of the springs, the material of the generally rectangular piece substantially filling the spaces between a majority of the springs. The resilient and compressible material may be a foam rubber.
Preferably the resilient and compressible material is in two layers, upper and lower, with co-operating passageways to receive the upper and lower ends of the springs, and the spaces between the springs being filled by separate pieces of the same or compatible resilient and compressible material. Whilst the filling may be by separate pieces, equally, said filling may be a lattice of a size equating to that of the upper and lower layers.
By matching the ratings of the springs to the compressibility of the resilient and compressible materials, a body support arrangement of any required firmness or softness to suit a user, can be provided.
Preferably the resilient and compressible material is so structured as to have different degrees of resilience and compressibility towards the outer upper and lower surfaces of the support means to simulate conventional upper and lower mattress and base parts, by having a graduated degree of resilience and compressibility across the thickness of the layer of resilient and compressible material, or desirably by providing upper and lower layers of resilient and compressible material, with each layer having a required degree of resilience and compressibility.
Where the requirement is for a conventional and continuous mattress, a combination of spaced springs and resilient and compressible filling can extend over the full width and length of a body support arrangement, and the softness/firmness of it can be constant over its full width and length. However, by selection of different springs and different resilient and compressible materials, and strategically positioning them across the width and over the length of the body support, it can be tailored to suit the particular requirements of the user, by creating zones of required softness and firmness.
To provide the required passageways through the resilient and compressible material, or the co-operating passageways through upper and lower layers of resilient and compressible material, it or they may have an initial width less than that required, and be provided with a number of cuts or slots of a length greater than that of the spring diameters, and transversely stretched to create oval passageways to receive the springs, of one (lateral) dimension equal to that of the spring diameters and a second (longitudinal) dimension greater than that of the spring diameters. With the springs inserted in the passageways, the or each layer of resilient material is held with a required transverse dimension, with free spaces to opposite sides of the springs in the longitudinal direction.
Whilst cuts or slots can allow the production of passageways, it is preferred that punched holes of an elongate narrow oval shape are formed through the or each piece to be stretched into the larger oval holes to receive the springs.
When used in conjunction with a suitable profiling support structure, on or within which is located appropriate mechanisms to lift and lower sectors of the support structure, a body support arrangement in accordance with the second embodiment, by having spaced springs and a resilient and compressible material, at least across the width of the arrangement at the position where one section is intended to pivot or bend in relation to an adjacent section, a smooth transition is provided between adjacent sectors set at different angular inclinations, free from any folding or rucking of the upper surface of the arrangement, to the considerable benefit of the user. This is largely consequential on the presence of free spaces to both sides of the springs in the longitudinal direction taking up the compression of the resilient material at the upper outer surface as it is caused to curve by the adjustment of the platforms.
Whilst spaced springs and fillings of resilient and compressible material can be provided over the full width and length of a body support arrangement intended for use with a profiling support structure, individual sectors of a body support arrangement in accordance with the invention, can be devoid of spaced springs and formed by the filling of resilient and compressible material.
For ease of manufacture, the springs for the invention may be relatively conventional pocketed springs, but with adjacent springs in each longitudinal row of greater than conventional pitch, and with the springs in one longitudinal row offset in relation to the springs in the immediately adjacent row. This generates a circumstance where the array of springs generates a triangular distribution with adequate space between adjacent springs to allow for spring movement without there being contact between adjacent springs. To provide added strength at the outer edges of the body support arrangement, an outer row of springs can be of greater compressive strength than elsewhere across the mattress, or a row of closely spaced springs of the same strength can be provided. Equally possible is the provision of an outer edge of resilient and compressible material of greater firmness than elsewhere across the body support arrangement.
With a body support arrangement of the invention, it has the capability of serving as a conventional mattress and sprung base arrangement and, additionally, as a mattress for use on an adjustable bed with an enhancement of those desirable characteristics of conventional beds, and the complete elimination of rucking at its surface.